diff --git a/libavcodec/audiotoolboxdec.c b/libavcodec/audiotoolboxdec.c
index 5c0a9de8f6..66055b79aa 100644
--- a/libavcodec/audiotoolboxdec.c
+++ b/libavcodec/audiotoolboxdec.c
@@ -483,7 +483,7 @@ static int ffat_decode(AVCodecContext *avctx, void *data,
     if (avctx->codec_id == AV_CODEC_ID_AAC) {
         if (!at->extradata_size) {
             uint8_t *side_data;
-            int side_data_size = 0;
+            int side_data_size;
 
             side_data = av_packet_get_side_data(avpkt, AV_PKT_DATA_NEW_EXTRADATA,
                                                 &side_data_size);
diff --git a/libavcodec/decode.c b/libavcodec/decode.c
index a4e50c0d03..de9c079f9d 100644
--- a/libavcodec/decode.c
+++ b/libavcodec/decode.c
@@ -66,7 +66,7 @@ typedef struct FramePool {
 
 static int apply_param_change(AVCodecContext *avctx, const AVPacket *avpkt)
 {
-    int size = 0, ret;
+    int size, ret;
     const uint8_t *data;
     uint32_t flags;
     int64_t val;
diff --git a/libavcodec/libvpxdec.c b/libavcodec/libvpxdec.c
index 1063c546b0..eddcea8941 100644
--- a/libavcodec/libvpxdec.c
+++ b/libavcodec/libvpxdec.c
@@ -220,7 +220,7 @@ static int vpx_decode(AVCodecContext *avctx,
     struct vpx_image *img, *img_alpha;
     int ret;
     uint8_t *side_data = NULL;
-    int side_data_size = 0;
+    int side_data_size;
 
     ret = decode_frame(avctx, &ctx->decoder, avpkt->data, avpkt->size);
     if (ret)
diff --git a/libavformat/adtsenc.c b/libavformat/adtsenc.c
index d937e2bea9..9e285752eb 100644
--- a/libavformat/adtsenc.c
+++ b/libavformat/adtsenc.c
@@ -169,7 +169,7 @@ static int adts_write_packet(AVFormatContext *s, AVPacket *pkt)
         return 0;
     if (!par->extradata_size) {
         uint8_t *side_data;
-        int side_data_size = 0, ret;
+        int side_data_size, ret;
 
         side_data = av_packet_get_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA,
                                             &side_data_size);
diff --git a/libavformat/apngenc.c b/libavformat/apngenc.c
index 88cd8054d6..7ad6a923d5 100644
--- a/libavformat/apngenc.c
+++ b/libavformat/apngenc.c
@@ -119,7 +119,7 @@ static int flush_packet(AVFormatContext *format_context, AVPacket *packet)
     AVIOContext *io_context = format_context->pb;
     AVStream *codec_stream = format_context->streams[0];
     uint8_t *side_data = NULL;
-    int side_data_size = 0;
+    int side_data_size;
 
     av_assert0(apng->prev_packet);
 
diff --git a/libavformat/flvenc.c b/libavformat/flvenc.c
index 5cf3ce8a1a..1cfcdc6392 100644
--- a/libavformat/flvenc.c
+++ b/libavformat/flvenc.c
@@ -902,7 +902,7 @@ static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)
 
     if (par->codec_id == AV_CODEC_ID_AAC || par->codec_id == AV_CODEC_ID_H264
             || par->codec_id == AV_CODEC_ID_MPEG4) {
-        int side_size = 0;
+        int side_size;
         uint8_t *side = av_packet_get_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA, &side_size);
         if (side && side_size > 0 && (side_size != par->extradata_size || memcmp(side, par->extradata, side_size))) {
             ret = ff_alloc_extradata(par, side_size);
diff --git a/libavformat/latmenc.c b/libavformat/latmenc.c
index 5ae677f5da..72b7f72f22 100644
--- a/libavformat/latmenc.c
+++ b/libavformat/latmenc.c
@@ -165,7 +165,7 @@ static int latm_write_packet(AVFormatContext *s, AVPacket *pkt)
             return ff_raw_write_packet(s, pkt);
         else {
             uint8_t *side_data;
-            int side_data_size = 0, ret;
+            int side_data_size, ret;
 
             side_data = av_packet_get_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA,
                                                 &side_data_size);
diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index eaed02bc92..105ed5197e 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -2007,7 +2007,7 @@ static int mkv_write_block(AVFormatContext *s, AVIOContext *pb,
     AVCodecParameters *par = s->streams[pkt->stream_index]->codecpar;
     mkv_track *track = &mkv->tracks[pkt->stream_index];
     uint8_t *data = NULL, *side_data = NULL;
-    int err = 0, offset = 0, size = pkt->size, side_data_size = 0;
+    int err = 0, offset = 0, size = pkt->size, side_data_size;
     int64_t ts = track->write_dts ? pkt->dts : pkt->pts;
     uint64_t additional_id;
     int64_t discard_padding = 0;
@@ -2122,12 +2122,10 @@ static int mkv_write_vtt_blocks(AVFormatContext *s, AVIOContext *pb, const AVPac
     int64_t ts = track->write_dts ? pkt->dts : pkt->pts;
     const int flags = 0;
 
-    id_size = 0;
     id = av_packet_get_side_data(pkt, AV_PKT_DATA_WEBVTT_IDENTIFIER,
                                  &id_size);
     id = id ? id : "";
 
-    settings_size = 0;
     settings = av_packet_get_side_data(pkt, AV_PKT_DATA_WEBVTT_SETTINGS,
                                        &settings_size);
     settings = settings ? settings : "";
@@ -2184,7 +2182,7 @@ static int mkv_check_new_extra_data(AVFormatContext *s, const AVPacket *pkt)
     mkv_track *track        = &mkv->tracks[pkt->stream_index];
     AVCodecParameters *par  = s->streams[pkt->stream_index]->codecpar;
     uint8_t *side_data;
-    int side_data_size = 0, ret;
+    int side_data_size, ret;
 
     side_data = av_packet_get_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA,
                                         &side_data_size);
diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index 6eeac8efa6..b8e45760ee 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -5788,7 +5788,7 @@ static int mov_write_single_packet(AVFormatContext *s, AVPacket *pkt)
             trk->par->codec_id == AV_CODEC_ID_AAC ||
             trk->par->codec_id == AV_CODEC_ID_AV1 ||
             trk->par->codec_id == AV_CODEC_ID_FLAC) {
-        int side_size = 0;
+        int side_size;
         uint8_t *side = av_packet_get_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA, &side_size);
         if (side && side_size > 0 && (side_size != par->extradata_size || memcmp(side, par->extradata, side_size))) {
             void *newextra = av_mallocz(side_size + AV_INPUT_BUFFER_PADDING_SIZE);
diff --git a/libavformat/mp3enc.c b/libavformat/mp3enc.c
index 14d4b6e0af..a3586e1f86 100644
--- a/libavformat/mp3enc.c
+++ b/libavformat/mp3enc.c
@@ -354,7 +354,7 @@ static int mp3_write_audio_packet(AVFormatContext *s, AVPacket *pkt)
 
         if (mp3->xing_offset) {
             uint8_t *side_data = NULL;
-            int side_data_size = 0;
+            int side_data_size;
 
             mp3_xing_add_frame(mp3, pkt);
             mp3->audio_size += pkt->size;
diff --git a/libavformat/rtpenc.c b/libavformat/rtpenc.c
index 63047beccc..9ef7e9094d 100644
--- a/libavformat/rtpenc.c
+++ b/libavformat/rtpenc.c
@@ -589,7 +589,7 @@ static int rtp_write_packet(AVFormatContext *s1, AVPacket *pkt)
         break;
     case AV_CODEC_ID_H263:
         if (s->flags & FF_RTP_FLAG_RFC2190) {
-            int mb_info_size = 0;
+            int mb_info_size;
             const uint8_t *mb_info =
                 av_packet_get_side_data(pkt, AV_PKT_DATA_H263_MB_INFO,
                                         &mb_info_size);
diff --git a/libavformat/segment.c b/libavformat/segment.c
index 2ff2b5372e..f67456fa57 100644
--- a/libavformat/segment.c
+++ b/libavformat/segment.c
@@ -873,7 +873,7 @@ static int seg_write_packet(AVFormatContext *s, AVPacket *pkt)
         return AVERROR(EINVAL);
 
     if (!st->codecpar->extradata_size) {
-        int pkt_extradata_size = 0;
+        int pkt_extradata_size;
         uint8_t *pkt_extradata = av_packet_get_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA, &pkt_extradata_size);
         if (pkt_extradata && pkt_extradata_size > 0) {
             ret = ff_alloc_extradata(st->codecpar, pkt_extradata_size);